Anticaries Agent Based on Silver Nanoparticles and Fluoride: Characterization and Biological and Remineralizing Effects—An In Vitro Study

OBJECTIVE: The aim of the study was to characterize and evaluate the stability, antimicrobial activity, cytotoxicity, and remineralizing effects of silver nanoparticles and fluoride anticaries agent (AgF) on staining dental enamel. MATERIALS AND METHODS: An experimental AgF solution was prepared and compared to silver diamine fluoride (SDF). First, the AgF was characterized and the stability was evaluated by transmission electron microscopy (TEM). Streptococcus mutans, Enterococcus faecalis, and Escherichia coli strains were used to evaluate the minimum inhibitory and bactericidal concentration and cytotoxicity performed using L929 fibroblastic cells by MTT test. Caries-like lesions induced by pH-cycling in human enamel were obtained, and then, the superficial microhardness, cross-sectional microhardness (CSMH), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were performed. Photographic images were taken to analyze the enamel staining. RESULTS: The AgF showed stableness in long term with bacteriostatic and bactericidal actions without cytotoxicity. Enamel remineralization, in surface and in depth (CSMH), was observed when the AgF was used, and it was similar to SDF. SEM showed enamel precipitation, and EDS observed the presence of P, Ca, Au, Ag, and Cl elements. Contrary to SDF, AgF did not stain the enamel. CONCLUSION: The nano silver fluoride anticaries agent tested presented long-term stability, superficial and in-depth remineralizing capacity with antimicrobial potential and biocompatibility and did not stain the enamel.